2016 Green Party presidential candidate Jill Stein said Tuesday that there's nothing nefarious about materials her campaign withheld from a Senate investigation into Russian interference in the 2016 election.

"We complied with everything actual relevant to the question of Russian interference. We turned over all of our communications with Russian media, Russian government, Russian business, although there was no communications to turn over," Stein told CNN's "New Day."

Stein said the only communications her campaign had with the Russian government and media were scheduling logistics of her 2015 trip to Moscow, which included a dinner hosted by RT, a Russian state-controlled TV channel, that was attended by Russian President Vladimir Putin.

"All of that was turned over. What we didn't turn over was material that basically protects the civil liberties of all Americans," Stein said Tuesday.

The Senate Intelligence Committee has requested communications with "Russian persons, or representatives of Russian government, media, or business interests," which prompted the campaign's objection that the panel was broadly targeting the communications of people "because they happen to be Russian immigrants or of Russian descent."

Stein said Tuesday that her campaign fulfilled all of the requests from the Senate committee and that they turned over their policy positions, but withheld internal discussions about policy.

"It's not like there's some, you know, special golden goose that we're protecting here or some vulnerable conversation," Stein said. "But rather we're standing up on a principle and that is the principle that's part of the First Amendment -- our right to basically freedom of association. That needs to be protected."

Stein has been connected to the Senate panel's investigation into Russia's 2016 election meddling in part because of her appearance at the now-infamous dinner hosted by RT. Michael Flynn, President Donald Trump's former national security adviser who has since pleaded guilty to lying to the FBI, was sitting at a table with Putin at the dinner -- along with Stein.

The Green Party candidate also praised WikiLeaks founder Julian Assange in 2016 after the organization posted a trove of hacked Democratic National Committee emails, saying there was "no question" he was a hero.